John Crepeau, Ph.D., P.E.

Professor
Department of Mechanical Engineering
University of Idaho
PO Box 440902
Moscow, Idaho 83844-0902
Tel: (208)885-5228
Fax: (208)885-9031
Email: crepeau@uidaho.edu

Left: Vienna, Austria, June 2006.
Right: The “mugshot,” circa 1996.

Crepeau
French (Crépeau): nickname for someone with curly hair, from a derivative of the Latin crispus, “curly-haired.”
Dictionary of American Family Names, Oxford University Press
ISBN 0-19-508137-4

To paraphrase the immortal David Letterman, “I can't believe they let me out of the house looking like that.”

Research Highlights

My colleague Ali Siahpush and I described the effect that the internal (volumetric) heat generation has on the movement and location of a solid-liquid phase change front. "Approximate solutions to the Stefan problem with internal heat generation" was published by the journal Heat and Mass Transfer. Computer modeling subsequently confirmed these solutions. The work performed in the two papers mentioned above led us to an exact, analytical solution to the Stefan problem with internal heat generation.

Josef Stefan, despite being eponymous for the Stefan-Boltzmann constant, the Stefan Number, the Stefan Problem, and the Stefan current among other things, is not a well-known figure in the scientific community at-large. This technical biography, "Josef Stefan: His life and legacy in the thermal sciences", describes such contributions as his empirical discovery of the T⁴ radiation law, which was later derived by his student Ludwig Boltzmann, his first accurate measurements of the thermal conductivity of gases, and his studies of ice formation on the polar caps. A less technical version of the paper, "From Rags to Research, the life of Josef Stefan", was published in bridges, a publication of the Office of Science and Technology of the Austrian Embassy of the United States. A paper describing his broad contributions to heat transfer was given at the 2008 ASME Heat Transfer Conference. At the 2009 ASME Heat Transfer Conference, I presented a paper describing a brief history of the fourth power radiation law. Stefan also worked with Josef Loschmidt in Vienna. An article describing their work can be found here.

Under a DOE-Nuclear Energy Research Initiative grant, Dr. Joy Rempe from the INL and I, along with our colleagues investigated various materials to be used within instrumentation devices for nuclear reactors. These included high temperature, irradiation resistant thermocouples, extension wires used in HTIR-TCs, and we measured thermal expansion coefficients of steels used in light water reactors.

Click on the thumbnail to see a full size version of the image which won the 2002 Kodak Award from the Visualization Society of Japan, and a brief synopsis of the phenomenon. The paper, "Dye-bubble interactions in an open channel flow", which describes the experiments that produced the image, appeared in Heat and Mass Transfer.

In studying the mechanics of fluids in nuclear reactors, we developed a set of similarity equations for buoyant flows driven by internal heat generation. What makes these similarity solutions unique is the exponentially decaying heat generation term.

After beginning at the University of Idaho, I was asked by the Idaho National Laboratory to study the drying of spent nuclear fuel. Some of our results were published showing an efficient drying method.

For my graduate and postgraduate studies I applied Powell and Percival's concept of the Spectral Entropy to various systems in order to quantify their self-organization. The first paper used spectral entropy concepts to analyze three dynamical systems, the second used spectral entropy to analyze turbulent time series data, and the third was a comparison of spectral and thermodynamic entropy.